Changing Item Data Values for Server?

[RyZup]

I'd like to discuss the possibilities if possible, to maybe do it with items that are already banned. for example Blaze rod is banned but we want to make lava cell a bit higher cost, so would it be possible to change the data value for blaze rod and lava cell and make them act as they are meant to? (despite the image.png that the client is offering by default anyways. as long as it functions as a bit more expensive fuel than atm, it would really help)

TL;DR: Possible ? Indirectly possible? How ? For Server only please ! NO SSP